There have been a few issues with Android phones losing connection to the SIM card. Some issues have been with Android and a few with Galaxy S4s running Android. Fortunately, there are a few fixes that seem to address all of them. So if you’re seeing the sim card not detected reboot error on your Android phone, this is for you.
Clear Android cache and data
Clearing the cache and data from the recovery menu seems to address a wide range of issues. That makes it a good place to start with the sim card one.
1. Navigate to Settings, Storage & USB, Cached data and select Clear cached data.
2. Power off the phone.
3. Boot the phone by holding the power and volume buttons. The Fastboot menu should appear.
4. Use the volume buttons to select Recovery and the power button to select it.
5. Let go of the power button but continue holding volume up and home until the Android logo appears. You should now be in the recovery menu.
6. Select Wipe cache partition with the volume down button and select it using the power button.
This seems to address the majority of sim card not detected reboot errors we have seen so far.
Galaxy S4 sim card not detected reboot error fix
If you’re still using a Galaxy S4, there is a special physical hack that should fix the error. It’s a little unscientific but many users swear by it.
1. Remove the back of the S4 to expose the sim.
2. Add a piece of cardboard or folded tape over the gray bezel that holds the sim.
3. Replace the back of the phone and reboot.
The phone should now work as normal. If the error persists, try a thicker piece of cardboard or tape, being careful not to crush the electronics.